Conventionally, a magnetic tape cartridge (recording medium cartridge) is provided with a cartridge memory to record unique information such as a serial number and a usage history of the magnetic tape cartridge other than a magnetic tape which is a recording medium. Because such the cartridge memory enables electric power and signals to be sent/received with no contact by electromagnetic induction, it is housed in a cartridge case of the magnetic tape cartridge (for example, see Japan patent laid open publication 2001-332064).
In the meantime, the conventional magnetic tape cartridge is set so that recording/reproducing and modifying data can be repeated. Therefore, it is difficult to simply verify data authentication, that is, whether or not it has been tampered with. Especially, in fields of medical care, law, and the like, the data authentication recorded in the tape cartridge is required to be assured, and it is needed to simply verify the data authentication.
In order to solve the problem, for example, a method for verifying the data authentication is contemplated, by recording information which shows data before tampering and comparing it with information produced from data which is reproduced from a magnetic tape in reproducing. However, there exists a problem in that the method results in not being able to assure data authentication if the magnetic tape and cartridge memory are changed to a magnetic tape after being tampered with and its corresponding cartridge memory.